The present invention relates to methods of correcting a program in a computer system, and more particularly to a method of correcting a program which resides in the main storage of a computer system and which is difficult to stop.
As a method of correcting a program in a computer system, there is a method of rewriting a program in its entirety in the computer system by reloading a corrected program. A method of correcting a program in a computer system without reloading such a program is disclosed in JP-A-3-97030 entitled "PROGRAM CORRECTING SYSTEM" in which a correcting program provided beforehand in the computer system is replaced with a program to be corrected.
Correction to a program having a reentrant structure constructed such that two or more tasks can be performed simultaneously, which is an object of the present invention, by reloading a corrected program, has been found impractical because it requires much labor for initialization in the reloading of the corrected program. The method of correcting a program by replacing a correcting program provided beforehand in the computer system with a program to be corrected has the following problems. For a program having a reentrant structure such as that of the present invention, it has been found that there is a danger that a program may be run by another command processor in the course of its correction, which should be avoided. It has also been found desirable even in such a case, to minimize the time in which the running of the program has been avoided to thereby minimize the influence on the availability factor of the system.